1. Field of the Invention
This invention relates to a novel blood substitute containing a modified hemoglobin as an oxygen-carrying material.
2. Brief Description of the Prior Art
It is known to use a blood substitute containing hemoglobin free from stromal components as an oxygen-carrying material (S. F. Rabiner et al. J. Ex. Med., vol. 126, p 1142 (1967)). On the other hand, it is also known that when the hemoglobin is infused into the circulation, it is rapidly excreted through the kidney and metabolized by other metabolic routes. In order to solve this problem, various proposals have been made, for example, a hemoglobin crosslinked with glutaraldehyde (Japan KOKAI No. 76-63920), a hemoglobin coupled with dextran (Japan KOKAI No. 77-51016), and a hemoglobin combined with hydroxyethyl starch (German patent Offenlegungsschrift No. 2616086). However, in the first case, oxygen is difficult to transfer at tissue, because oxygen affinity of the hemoglobin is too tight. In case of the latter two proposals, high concentration of the hemoglobin often leads to unfavorable results because of its high viscosity.